Universal seal nut



Patented Mar. 15, 1949 a UNIVERSAL SEAL NW1 7 Louis B. Courtot; Cleveland, Ohio, assignor to The Weatherhead Company, Cleveland, Ohio, a corporation of Ohio Application November 19, 1945, Serial No. 629.514

4 Claims. 1

My invention relates to sealing threaded fittings and methods of machining deformable material.

It is an object of my invention to provide an improved universal seal nut for securing a universal fitting and sealing the threaded joint v thereof.

It is an object of my invention in general to prevent leakage of fluid through threaded joints,

and to render threaded joints both leak-proof and corrosion resistant.

A further object of my invention is to provide a method of machining deformable material with precision.

Still another object of my invention is to form accurate screw threads in packing material such as rubber-like inserts.

A further object of my invention is to provide a rapid, reliable method of machining elastic substances accurately.

Other and further objects, features and advantages will become apparent as the description proceeds.

In carrying out my invention in accordance with a preferred form thereof for fastening a universal fitting and sealing it, I provide a sealing nut having a circular recess at one face thereof concentric'with the threaded hole in the nut and containing a packing member or insert bonded to the surfaces of the nut in the recess. The insert is made of greater thickness than the' depth of the recess so that it protrudes from the face of the nut, and the packing member is also provided with an opening having threads forming a continuation of the threads in the remainder of the nut. The resilient or elastic insert of packing 'is composed of rubber or rubber-like material,

preferably a synthetic substance resistant to acid in order that the nut may be protected from corrosion by utilizing a suitable process involving an acid solution such as plating or anodizing.

In order to form an accurate screw thread in the rubber-like insert, the nut with the insert after the latter has been bonded thereto, is chilled to a temperature low enough to cause the insert to solidify. Preferably, the drill is also chilled while the hole is cut through the insert and the nut. Afterwards the nut and the insert are maintained at a low temperature while being tapped, and the tap is preferably chilled. I

A better understanding of the invention will be afforded by the following detailed description considered in conjunction with the accompanying drawing and those features of the invention, which I believe to be novel and patentable, will be pointed out in the claims appended hereto,

2 In the drawing; 1 .Fig. 1 is a plan view of a sealing nut for a universal fitting, forming an embodiment of my invention;

Fig. 2 is a sectional view of the device of Fig. 1

' before it has been tapped;

Fig. 3 is a sectional view of the finished sealin nut of Fig. 1;

Fig. 4 is a schematic diagram illustrating the method of chilling the elastic portion'of the sealing nut in accordance with my invention for the purpose of drilling the nut;

Fig. 5 is a schematic diagram correspondin with Fig. 4 illustrating the step of tapping the nut; and

Fig. 6 is a fragmentary diagram of a universal fitting applying the sealing nut in accordance with my invention.

Like reference characters are utilized throughout the drawing to designate like parts.

Referring Fig. 6 of the drawing, in order that a threaded fitting such as an elbow II, for example, may be mounted in any position in another part such as a bulkhead l2 having a threaded opening receiving the nipple I3 of the elbow II, I provide a sealing nut [4 shown in greater detail in Fig. 3 having a conventional nut body [5 with a recess l6 at one face concentric with the hole in the nut and containing a threaded packing member or insert iii of greater depth than the recess l6 so as to protrude from the nut face l9. In this manner the fitting H is removable without giving rise to leakage when replaced or turned to a different position, it is unnecessary to use pipe threads of the usual tapered form and no thread filling compound or cement is required to prevent leakage at the nut threads l1. 7

When the fitting II has been turned to the desired angle, the sealing nut I4 is tightened up against .the surface 2| of the bulkhead I 2 so as to compress the packing member or insert 'l8 against the surface 2i and also into the screw threads 22 and the external surface of the fitting I I. In this manner a seal is produced around the threaded joint by reason of the intimate contact of the packing material l8 with the surfaces in question.

The packing member or insert I8 is preferably composed of elastic resilient material,.and preferably it is acid-resistant. It may be a rubber-like material like natural rubber or a synthetic rubber-like composition that is acid resistant. In making the nut M, the recess I6 is formed and the insert I 8 is moulded in place in ensure the recess it so as to be bonded thereto. The complete nut M is threaded so that a continuous screw thread runs through the insert i3 and the nut body I5. In order that the portion ii of the thread in the body l5, and the portion 2 3 of the thread in the insert is form an accurate continuation of each other and the portion 33 of the thread in the elastic material it will be true screw threads accurately cut, the threads in the body portion i5 of the nut M and the insert i3 are preferably cut in the same operation. While the machining operation is performed the insert 93 is suiilciently chilled to render it relatively rigid or substantially solidified. Although a rubber Washer 23 may be bonded in a nut blank 2?, already provided with an opening 23, I prefer to mold a rubber disc in a cylindrical socket in a non-perforated blank and to drill both the insert and the blank at the same time to form the open Referring to Fig. 4, an elastic body 3| which is I to be machined for example, the insert for a sealing nut, is confined within a suitable rigid member, in this case a nut blank 32 having the recess l6 into which the elastic rubber-like insert 3| has been bonded. A suitable jig is provided for holding the work and guiding the cutting tool. For example, as illustrated, a pair of clamping jaws 33 and 34, one of which is movable, are provided in the jig for holding the piece 32 supporting the elastic member 3|. A jig strap 35 is provided, having an opening 36 for receiving a drill 31, a hardened bushing 38 preferably being provided in the opening 36 to protect the jig strap 35. In order to insure maintenance of the elastic member 3| at relatively low temperature during machining operations, not only the member 3| but also the entire jig and the cutting tool 31, are subjected to cooling by surrounding them with a cooling substance.

The parts to be chilledmay be maintained at the desired low temperature by immersing them in a suitable fluid or a liquid which has been maintained at a low temperature by suitable refrigerating apparatus or a separate refrigerating substance. However, I prefer to avoid the employment of a liquid which may have the effect of rendering the surface of the elastic block 3| slippery, or may interfere with the cutting action of the tool 31. Accordingly, I preferably immerse the parts in a refrigeration liquid such as alcohol and I employ a refrigerant of the type which passes directly from a solid, which sinks in alcohol, to the gaseous state, such as dry ice or solidifled carbon dioxide, for example.

As illustrated in Fig. 4, a jig including the clamping jaws 33, 34 and the drill guide 35 are preferably secured to a base block or a bench composed of insulating material such as wood planking 39, asbestos board, or the like, and a housing is provided composed of insulating boards or plates 4| enclosing a mass of alcohol and dry ice 42 which chills the space around the jig, the nut blank 32, the elastic insert 3| and the drill 31 so as to maintain all of these parts at a low temperature. Good thermal insulation is desirable from the standpoint of economy in the em- 4 ployment of the refrigerating material. The temperature is depressed sufficiently to cause the material of which the insert i8 is composed to solidify and become rigid.

After the insert 3| and the nut blank 32 have been drilled, the screw threads 23 and ll are cut in by means of a tap 33, preferably maintaining the work, the jig, and the tool 83 at the same reduced temperature by means of the alcohol immersion dry-ice packing 32.

After the completed sealing nut with both the elastic and metal portions threaded has been removed from the dry ice, it resumes normal ambient temperature and the resilient insert l3 resumes its elastic resilient characteristics but with the thread accurately cut with the same pitch and depth as the portion of the thread i! in the metallic body l5.

When the nut it is drawn against the bulkhead surface 2|, the face at of the resilient insert bears against the bulkhead surface 2| so as to form a seal between the nut i4 and the surface 2|; simultaneously the compression of the resilient insert 08 after the nut i4 is drawn against the surface 2i also forces the threaded material inward causing the threads 24 in the elastic insert is to contact tightly upon the threads 22 in the nipple i3. Thus a seal is formed between the nut it and the fitting ll. leakage can take place between the fitting i and the bulkhead l2.

For the insert i8 a natural rubber compound may be employed which becomes substantially solid or unelastic where the temperature is as I low as 0 F. Preferably, however, I employ an acid-resistant compound or a synthetic packing compound whenever the sealing nut is to be anodized or coated. Such corrosion preventing treatment involves the use of an acid solution.

o Since such solution does not attack the insert 3|, the nut may be protected against corrosion after the insert 3| has been bonded in the recess i6 without any injury to the insert 3|.

Inasmuch as the threads as well as the remaining surfaces of the metallic nut body l5 are to be protected against corrosion, the corrosion treatment such as anodizing and electrolytic coating is given after the synthetic insert has been bonded to the nut and after the threads have been cut in both the insert l8 and the metal- 'lic nut body I5.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed'claims.

What is claimed is:

l. A universal connection comprising in combination a bulkhead having a. threaded opening, a fitting having a threaded nipple rotatably mounted in said bulkhead opening, and a universal seal nut having a body of relatively rigid material with a threaded bore to fit said nipple, said body having a recess formed around its threaded bore at the face adjacent said bulkhead, a sealing element of relatively soft resilient rubber-like material disposed in the recess of said body with said element initially projecting past said body face, a peripheral portion of said element being confined by the radially outer wall of said recess, said resilient element also being Consequently, no

threaded to fit said nipple with the threads of said resilient element having a depth substantially equal to the depth of the body threads and forming a smooth-walled continuation of the threads of said body, tightening of said nut against said bulkhead resulting in deformation of said confined resilient element to ur e its threads in tight and uniform sealing engagement with the entire area of the threads of the nipple with the outer face of said element in sealing engagement with the surface of said bulkhead.

2. A universal connection comprising in combination a fiat bulkhead having a threaded opening, a fitting having a threaded nipple rotatably mounted in said bulkhead opening, and a universal seal nut having a body of relatively rigid material with a threaded bore to fit said nipple,

said body having a recess formed around its threaded bore at the face adjacent saidbulkhead, a sealing element of relatively soft resilient material disposed in the recess of said body andbonded to said body with said element initially projecting past said body face, a peripheral portion of said element being confined by the radially outer wall of said recess, said resilient element also being threaded to fit said nipple with the threads of said resilient element having a depth substantially equal to the depth of the body threads and forming a smooth-walledcontinuation of the threads of said body, tightening of said nut against said bulkhead resulting in deformation of said confined resilient element to urge its threads in tight and uniform sealing engagement with the entire area of the threads of the nipple with the outer face of said element in sealing engagement with the surface of said bulkhead.

3. A sealing nut having a body of relatively rigid material with a threaded bore, said body having a recess formed around its threaded bore at one face adjacent said bulkhead, a sealing element of relatively soft rubber-like material disposed in the recess of said body with said 6 element initially projecting past said body face, a peripheral portion of said element being confined by the radially outer wall of said recess, said resilient element also being threaded with the threads of said resilient element havinga depth substantially equal to the depth of the body threads and forming a smooth-walled continuation of the threads of said body.

4. A sealing nut having a body of relatively rigid material with a threaded bore, said body having a recess formed around its threaded bore at one face adjacent said bulkhead, a sealing element of relatively soft resilient material bonded in the recess of said body with 'said element initially projecting past said body face, a

peripheral portion of said element being confined by the radially outer wall of said recess, said resilient element also being threaded with the threads of said resilient element forming a continuation of the threads of said body.

LOUIS B. COURTOT.

REFERENCES CITED The following references are of record the file of this patent:

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